1. Field of the Invention
The present invention generally relates to a polygon (this term is proper without concern) mirror device, and more particularly to a polygon mirror device with discontinuous angles of reflections.
2. Description of Prior Art
In prior arts which a laser is employed as a light source in a scanning projector, a reflectors combination swing control by a MEMS (Micro Electro Mechanical System) is generally utilized for the scanning projection of the scanning projector. Alternatively, a multiple polygon mirrors rotating combination also can be utilized for the scanning projection. Speaking of the reflectors combination swing control, the MEMS lags the physical motion in the swing control because an air damping exists during the control of the swing angles of the reflectors and the damping oscillations of the reflectors and the whole MEMS, the control of swing angles of the reflectors in the MEMS has to be more considerate to precisely control the accuracy of the scanning projection procedure.
Mentioning about the multiple polygon mirrors rotating combination, the drawbacks of the aforesaid reflectors combination swing control by the MEMS can be avoided. Due to the angle control of the reflectors is discontinuous, the scanning projection time can be shortened and the aforesaid kinds of dampings also can be prevented to simplify the control procedure of the scanning projection. However, Most of the multiple polygon mirrors rotating combinations today change the angle discontinuously to control the angles of reflecting the light source. Meanwhile, all the compositions of the multiple polygon mirrors rotating combinations and respective driving motors occupy a quite large space which truly violates the almost mainstream of miniaturization design. Moreover, the high speed rotations of the multiple motors and the multiple polygon mirrors cause vibrations, noises of the whole scanning projector and lead to disadvantages of instability and a short usage lifetime of the products.
Consequently, there is a need to develop a polygon mirror device with discontinuous angles of reflections to efficiently solve the problems of laser light source scanning projector according to prior art.